PHYS 221L Midterm, Fall 2007

Physics 221L Midterm – November 2007 1. In the Capacitors and dielectrics experiment, you perform the necessary measurements and obtain the following numbers: Measured Values Diameter D 16.3 ±0.3 cm Separation d (spacer ) 0.32±0.01 mm Cair (measured) 540±6 pF Cd (meas. W/dielectric) 1437±19 pF Find the permittivity of free space ε0. Compare to the literature value of ε0 (8.85x10-12 SI) and comment. Find the dielectric constant of the dielectric spacer. 2. What are Miller indices? 3. Why did you move both source and detector in the microwave diffraction experiment? 4. Three students measure the length of a cable (in cm) with the following results: 134.25± 0.12, 133.5±0.3 and 135.1±0.5. Combine the results of these measurements to determine the value of the cable. 5. A polarizer has a characteristic direction; this is the direction of the plane of polarization of light transmitted through the polarizer. Given a polarizer, a glass plate and a source of light, how would you determine the characteristic direction of the polarizer? Give exact details.